Amino-naphthalene sulphonic acid dye intermediate prepn. - by pump-hydrogenating nitro-naphthalene-sulphonate salts using fresh and used Raney nickel catalyst mixt

• Main Authors: STEFFAN,GUIDO,.DR, KAISER,REINHARD,.DR, BARTH,OTTO, BEHRE,HORST,.DR, ZANDER,JUERGEN,.DR, BECKER,HANS-JOACHIM,.DR
• Format: Patent
• Language: English; German
• Published: 27.07.1978
• Edition: 2
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; ORGANIC CHEMISTRY; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

Aminonaphthalene-sulphonic acids (II) are prepd. by catalytic hydrogenation of nitronaphthalene sulphonate salts with H2 in the presence of Raney Ni catalysts at increased temp. and pressure. Novelty consists in (a) preparing a mixt. of Raney Ni catalyst already used in hydrogenation and of fresh Raney Ni catalyst in a water-contg. suspension; (b) heating this suspension to 100-180 (100-160) degrees C. under H2 pressure 100-300 (150-200) bar and (c) introducing into the suspension, at this temp., a 10-30 wt.% water-contg. soln. or suspension or nitronaphthalene-sulphonic acid, (I), having pH 6-9 (7-8), in a way such that the (I)-content in reaction mixt. is =3 wt.% w.r.t. total reaction mixt. wt. (II) are dyestuffs- and dyestuff precursor intermediates. Process may take place continuously. Yields of (II) are increased by up to 10%, compared to batch hydrogenation, and can reach 95-99% w.r.t. (I). Space/time yields are 1-3 kg. (II)/l. reactor vol. hr. Catalyst costs and catalyst poisoning are reduced.